There has been a murder in a reunion party. Chris Lawrence was found in the closet, stabbed in the back (how ironic). You have deduced that the only suspects are those at the party: Sam from Stanford, Yvonne from Yale, Harry from Harvard, Carrie from Cornell, Bart from Brown, Diana from Dartmouth, and Peter from UPenn (Chris was from Columbia). Problem is, the only lead you have is a piece of paper that Chris wrote:
2 + 1 + 19 + 5 - 64
Who is the killer?
When you interview all of the suspects, you find that one thing they all say is along of the lines of, "Chris was always the first of his class, and received letters after letters of congratulation."